Current batteries for portable electronic equipment, such as a hand held mobile devices need to be recharged fairly often. With increasing functionality of such equipment, come increasing power demands. The desired portability of the electronic equipment leads to space constraints, further increasing the demands on battery performance. The energy density of existing batteries is proving insufficient to keep pace with the power requirements of portable electronic equipment.
Micro fuel cells may utilize water vapor recovered from hydrogen/air proton electron membrane fuel cells to generate hydrogen via a hydrolysis reaction with a water reactive fuel such as a chemical hydride. A mechanism may be used to regulate the hydrogen generation rate by regulating water vapor provided to the fuel. A membrane type valve has typically been used to regulate water permeation through a membrane based on the pressure difference across the membrane. While such a membrane based water regulation approach works well for relatively low power density fuel cell based power generators, such approaches tend to use a tortuous diffusion path for the water vapor, resulting in a significant increase in thickness or operating temperature to scale to higher power, negatively affecting power generator energy density.